The Applicant has developed a wide range of printers that employ pagewidth printheads instead of traditional reciprocating printhead designs. Pagewidth designs increase print speeds as the printhead does not traverse back and forth across the page to deposit a line of an image. The pagewidth printhead simply deposits the ink on the media as it moves past at high speeds. Such printheads have made it possible to perform full colour 1600 dpi printing at speeds in the vicinity of 60 pages per minute; speeds previously unattainable with conventional inkjet printers.
Printing at these speeds consumes ink quickly and this gives rise to problems with supplying the printhead with enough ink. Not only are the flow rates higher but distributing the ink along the entire length of a pagewidth printhead is more complex than feeding ink to a relatively small reciprocating printhead.
The ink conduits can be blocked by air bubbles. Air bubbles can form in the ink conduits when dissolved gasses come out of solution during periods of inactivity. If the bubble is big enough, it can completely occlude the conduit and block the ink flow. The bubble can pin to the inside of the conduit such that it requires a finite force to be applied to move it, as if it had a static coefficient of friction. The bubble resists moving with the ink flow and can starve areas downstream of the bubble, or cause a detrimental pressure increase upstream of the bubble.